1. Field of the Invention
This invention relates to an apparatus for delivering both rotation force and fluid to a hollow shaft and is more particularly concerned with a ratchet and hydraulic seal assembly for rotating hollow shafts.
2. Description of the Prior Art
In the past, drilling rigs for drilling for oil, gas, or water have employed drilling pipes which are successively connected together so as to form a power train which rotates a drilling bit and urges the drilling bit progressively into the ground. In doing so, both rotational force and a down force is applied to the upper end portion of the uppermost pipe. Drilling fluid, such as water or "mud" is usually pumped through a metal sleeve and through ports in a power transfer pipe so that this drilling fluid passes down through the tandem arranged drill pipes and out around the drill bit so as to lubricate the drill bit and also provide a return fluid which washes out or flushes the drill hole as it passes externally of the drill rods up and out of the drill hole.
The difficulty with the prior art hydraulic seal assemblies is that they readily wear and are subjected to the abrading drilling fluid. Thus, in use, these hydraulic seal assemblies leak.